0.940 ajustable gas block for bull barrel AR availability?

Spinalmath

Spinalmath

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Hi guy and merry Xmas!
I'm trying to find an adjustable gas block that would fit my AR15 (ASA 16 bull barrel) with a diameter of 0.940? I don't seem to find any, the bigger available is 0.936. Am I chasing a unicorn here? If I can't find any, is there any other way to adjust the gas pressure? I just got a ultra LMOS carrier group and my adjustable gas block is too small (0,936).

Thanks
 
The correct nominal size is .9375". (gas block should be ~.9375"-.9385", journal should be ~.9358"-.9368")

If the journal on your barrel is ACTUALLY measuring .940", then it's been turned too large. Using a clamp-on .9375" gas block, you should be able to squeeze it on there (because they are split, you can wedge the bottom apart to slide it on). A set-screw type is unlikely to fit unless it's bigger than .940".

IIRC, JP makes a clamp-on adjustable gas block in that size (you can buy it through Brownells)...........although I'm not terribly impressed with the quality of JP gas blocks.

Another option (again, assuming the journal is actually .940"), is to find someone with a 24mm (.9448") reamer and have them open the gas block diameter. I would only recommend that for a set screw type, and even at that, I would say it's a less than ideal solution.

Either that or find someone with a honing machine.
 
Last edited:
*MALICE* said:
The correct nominal size is .9375". (gas block should be ~.9375"-.9385", journal should be ~.9358"-.9368")

If the journal on your barrel is ACTUALLY measuring .940", then it's been turned too large. Using a clamp-on .9375" gas block, you should be able to squeeze it on there (because they are split, you can wedge the bottom apart to slide it on). A set-screw type is unlikely to fit unless it's bigger than .940".

IIRC, JP makes a clamp-on adjustable gas block in that size (you can buy it through Brownells)...........although I'm not terribly impressed with the quality of JP gas blocks.

Another option (again, assuming the journal is actually .940"), is to find someone with a 24mm (.9448") reamer and have them open the gas block diameter. I would only recommend that for a set screw type, and even at that, I would say it's a less than ideal solution.

Either that or find someone with a honing machine.
Click to expand...

Thanks for your answer, here is picture that shows it all. I can't find the JP ajustable gas block 0.9375 on Brownells (only .750). Any other thought where I could find it?


Gas block.jpg
Best regards!
 

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*MALICE* said:
In re your picture, it says your jp adj gas block fits there. So you already have a JP adj gas block?
Click to expand...
Yup, I bought the JP adjustable gas block .936 bore (clamp-on). It fits the barrel just in front of where it's supposed to be... but doesn't fit over the gas port. That's the problem
 
Try using something as a wedge in the gap (a screwdriver for example) to expand the bore enough to slide it on the journal.
 
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